The present invention relates to torquing systems. More particularly, in one embodiment the present invention relates to an improved torque wrench system having multiple torque stations providing for the makeup and removal of a plurality of threaded bolts or nuts. In one embodiment the improved torquing system includes both high torque and low torque phases of the makeup or removal process. In one embodiment both high speed and low speed phases are provided.
In the makeup or break down of large structures, such as, for example rig risers, the sections of the riser are flanged together with bolts threadably engaging the flanges on the end of each section, and made up very tightly to complete the structure. There are numerous other types of structures which use this same system of makeup, i.e., very large bolts through flanges connecting sections of structures.
Flanged riser joints use specially designed bolts that must be torqued to a precise preload. Typically, flanged riser connectors in the offshore drilling industry use six (6) bolt flanges with each bolt straddling an auxiliary line position. During the operation of running the blow out preventer or “BOP” (e.g., initially installing the BOP and riser), an upper flange of a riser joint in the riser string can be landed and supported on the riser spider (e.g., with the spider dogs in an extended state). A new riser joint can stabbed or placed on top of the supported riser joint and the plurality of riser bolts can be turned down and torqued thereby making up the connection. This process can be repeated as many times as needed until the riser string reaches the sea floor and can be attached to the wellhead.
In a typical rig riser structure the flanged sections of the risers include six (6) holes radially spaced apart in about sixty (60) degree increments (around the 360 degree bolt circle of the riser section flanges). The riser string typically extends from the drilling rig above the surface of the water to the wellhead located at sea floor. In deepwater installations the depth of water typically exceeds 5,000 feet. Riser sections are typically provided in 75 foot lengths, yielding a minimum of 67 riser sections or joints and 67 multiplied by 6 (or 402) bolts which must be properly tightened or made up (when installing the riser) or loosened or broken out (when removing the riser).
Presently, when installing or removing riser sections or joints, torque wrenches are manually positioned and operated to individually tighten or loosen each of the six bolts for each riser section or joint. In an effort to speed up the process two torque wrenches operated by two operators can be used addressing two bolts at the same time. However, each operator must individually position and operate his torque wrench on the head of each bolt when tightening or loosening. The operator continues around the flange until all six bolts have been torqued. Additionally, after completing each bolt, the operator must manually remove the torque wrench from the made up bolt and position the torque wrench on the next bolt. After all bolts are torqued down, the spider dogs are retracted and the riser string (e.g., plurality of riser joints and BOP) is lowered to allow the placement and make-up of the connection to the next riser joint section.
This manual process is time consuming and slows down both the initial installation along with the removal of the riser. Additionally, the operators of these torque wrenches can become tired slowing down the process, making mistakes, damaging equipment, and/or causing injury. Due to increasing rig day rates and improved HSE requirements, it is desirable to create a tool that can preload each riser flange connection quicker and without human presence at the well center. This would improve rig operational efficiency as well as safety performance. In a typical yearly operation of a drilling rig the riser string can be retrieved (tripping out) and installed (tripping in) between two and twenty four times.
While certain novel features of this invention shown and described below are pointed out in the annexed claims, the invention is not intended to be limited to the details specified, since a person of ordinary skill in the relevant art will understand that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation may be made without departing in any way from the spirit of the present invention. No feature of the invention is critical or essential unless it is expressly stated as being “critical” or “essential.”